Quote

How does Kyuden Hida work with reactions to entering play and discarding the other cards. For cards like Wayfarer's Camp and Invoke the Divine, reactions to playing cards happen mid-resolution (I think?). Is this the same?

For two concrete examples:
I trigger Kyuden Hida and reveal Favorable Dealbroker, Hida Guardian, Iron Mine.
If I buy the Favorable Dealbroker, does his reaction trigger before we discard the Hida Guardian & Iron Mine? If yes, and I select the Hida Guardian, does it still get put into the discard during the "discard the rest" part of the effect?

Same question, but with Shihobu instead of the Dealbroker. Can I take the Iron Mine?

By the time Favorable Dealbroker and/or Kaiu Shihobu can trigger their reaction, the other cards seen by Kyūden Hida have been discarded. You fully discard the looked-at cards before the reaction window for playing Dealbroker/Shihobu opens.
Note that this is different from Wayfarer’s Camp/Invoke the Divine because those cards instruct you to play multiple cards, whereas Kyūden Hida only has you play one (so you can resolve its full effect before opening the reaction window).

[Tyler Parrott, 26 Mar 2020]